Issue 17286: Message Size should be included as part of DDSI/RTPS Messages (ddsi-rtps-rtf)
Source: ADLINK Technology Ltd (Angelo Corsaro, PhD., angelo.corsaro(at)adlinktech.com)
Nature: Revision
Severity: Critical
Summary: The DDSI/RTPS wire protocol currently expects the transport to provide the size for the message -- said in other terms, the current version of the protocol can only work with message oriented transports, such as UDP/IP. 


This assumptions should be dropped in order to enable the use of DDSI/RTPS over stream oriented transports such as TCP/IP.



One possible approach to overcome this limitation w/o breaking backward compatibility with other implementation is to add a new sub-message element, say MESSAGE_LEN structured as follows:


+--------+--------+--------+--------+
|   ID   | Flags  | octect2NextSME  |
+--------+--------+--------+--------+
|          Message Length           |
+-----------------------------------+


In addition, for efficient parsing, if the sub-message above, when used, should be always placed right after the RTPS header.
Resolution: 
Revised Text: 
Actions taken:
March 30, 2012: received issue
Discussion: 

End of Annotations:=====

m: webmaster@omg.org
To: <issues@omg.org>
Subject: Issue/Bug Report


*******************************************************************************
Name:            Angelo Corsaro
Employer:        PrismTech
mailFrom:        angelo@icorsaro.net
Terms_Agreement: I agree
Specification:   DDS Interoperability Wire Protocol
Section:         8.3
FormalNumber:    formal/2009-01-05
Version:         2.1
Doc_Year:        2009
Doc_Month:       January
Doc_Day:         05
Page:            29
Title:           Message Size should be included as part of DDSI/RTPS Messages
Nature:          Revision
Severity:        Critical
CODE:            3TMw8
B1:              Report Issue


Description:


The DDSI/RTPS wire protocol currently expects the transport to provide the size for the message -- said in other terms, the current version of the protocol can only work with message oriented transports, such as UDP/IP. 


This assumptions should be dropped in order to enable the use of DDSI/RTPS over stream oriented transports such as TCP/IP.



One possible approach to overcome this limitation w/o breaking backward compatibility with other implementation is to add a new sub-message element, say MESSAGE_LEN structured as follows:


+--------+--------+--------+--------+
|   ID   | Flags  | octect2NextSME  |
+--------+--------+--------+--------+
|          Message Length           |
+-----------------------------------+


In addition, for efficient parsing, if the sub-message above, when used, should be always placed right after the RTPS header.